***!!! iMovie just sits there and does nothing... Will NOT export to camera roll

I just purchased a brand new iPhone 5S and downloaded iMovie. I can edit clips just fine, but when I try to export to the camera roll it does nothing. I can only export to iTunes out of all the options, but that doesn't do anything as far as sharing clips from my phone. I have uninstalled and reinstalled iMovie several times (which clears my projects) and still no luck. I used iMovie on my previous 4s and had no issues. Why does this not work? Is it going to be fixed? By the looks of a quick Google search, I'm not the only one who is ****** that they paid for an "Apple" app, and it doesn't work. Fix this please, or let me know what I'm doing wrong.